It is often necessary to interface low voltage integrated circuits with higher voltage integrated circuits. In particular, a low voltage integrated circuit may need to interface with a bus operating at a higher supply voltage, so that a driver buffer is required for proper interfacing. It is desirable for such a buffer circuit to be manufactured with the same technology process as the low voltage integrated circuit, so that the buffer is integrated with and becomes part of the integrated circuit. However, low voltage integrated circuits may have smaller gate-oxide breakdown voltages than higher voltage integrated circuits. It is therefore desirable for a buffer circuit designed with a low voltage technology process to drive a bus at higher voltages without suffering gate-oxide breakdown.